If
you are interested about the No$GBA emulator (and some of its
utilities), here are the most frequently asked questions related to it:
How can I play DS roms with No$GBA Emulator for my PC?
Here the steps that you should follow to make use of the No$GBA
Emulator:

Download the file for No$GBA Emulator.

Copy the file to a specific folder.

For zipped files: extract the emulator file into a new folder

For unzipped files: copy and paste the emulator file to a new folder

Download the DS ROMs. If it is unzipped, just copy the files to the same folder where the emulator file is located.

Select the NoGBA.exe file and choose the ROM you want to play afterwards.

Note: If the abovementioned step result to a “Fail to Read Data” output, follow these instructions:

Go to Options menu. Select Emulator. Select NDS Back-up Media.

Select a save type (typically the EEPROM 64Kbytes).

Select Options and choose Save.

Reorganize the cartridge.

These
are just the steps that you need to follow to make the No$GBA emulator
work on your PC. After following these instructions, the emulator will
be working fine afterwards.